Studies of C_4 and C_(10) methyl ester flames

摘要

The oxidation of three model biodiesel fuels, namely methyl butanoate (C_5H_(10)O_2, CAS No. 623-42-7), methyl crotonate (C_5H_8O_2, CAS No. 623-43-8), and methyl decanoate (C_(11)H_(22)O_2, CAS No. 110-42-9) was investigated in laminar premixed and non-premixed flames. The experiments were conducted in the counterflow configuration at atmospheric pressure, for a wide range of equivalence or inert-dilution ratios, and elevated reactant temperatures. Laminar flame speeds and local extinction strain rates were determined by measuring the flow velocities using digital particle image velocimetry. The experimental data were compared against those derived for flames of n-alkanes of similar carbon number, in order to assess the effects of saturation, the length of carbon-chain, and the presence of the ester group. Several recent chemical kinetic models were tested against the experimental data, and major differences were identified and assessed. The accuracy of the Lennard-Jones potential parameters assigned to the methyl esters in the transport databases of the different models was evaluated and new values were estimated. Insight was provided into the high-temperature kinetic pathways of methyl esters in flame environments. Additionally, the reduced sooting propensity of methyl ester flames compared to n-alkane flames was investigated computationally.